Electrically heated alignment pad

ABSTRACT

A pad utilizable in padding, levelling or aligning girders, rails or any other constructional or structural elements. The pad comprises at least one thermoplastic plate member and an electric heater for heating the thermoplastic plate member to soften or melt to cause the overall thickness of the padding material to be reduced to a value sufficient to bring an article or machine to a predetermined level. The plate member is made of a thermoplastic polyester material of a composition which substantially comprises a crystalline polyester segment having a high melting point or a softening point and a non-crystalline polymer segment having a low melting point.

United States Patent 1191 Furuishi et a1.

1 1 ELECTRICALLY HEATED ALIGNMENT PAD [75] Inventors: Haruhisa Furuishi, Suita; Yoshihiro Murata, Katano; l-lidenori Suzaki, Hirakata; Misao Sumoto; Hiroshi lmanaka, both of Otsu, all of Japan 173] Assignees: Matsushita Electric Industrial Co.,

Ltd.; Toyo Boseki Kabushiki Kaisha, Japan 22 Filed: Oct. 1, 1974 211 App]. No.:51l,471

[30] Foreign Application Priority Data Oct. 1, 1973 Japan 48-110851 [52] US. Cl. 219/528; 219/213; 219/549; 238/283; 260/860 [51] Int. Cl. H05B 3/34 [58] Field of Search 219/213, 522, 523, 528, 219/529, 536,548, 549; 238/281, 283, 349;

[56] References Cited UNITED STATES PATENTS 2,185,692 l/l940 McCleary 1. 219/528 X 2,735,926 2/1956 Langlois 219/528 1 1 Dec. 2, 1975 2,741,692 4/1956 Luke 219/528 2,938,992 5/1960- Crump v l 219/528 3,584,198 6/1971 Doi ct a1 i l .1 219/549 3,662,951 5/1972 Smith ct a1..., 238/281 3,682,846 8/1972 Sano et al7 60/860 X 3,688,984 9/1972 Sonneville 238/349 3,745,302 7/1973 Bond 219/213 3.766,]46 10/1973 Witsiepe 260/860 X 3,784,520 1/1974 Hoeschele 260/860 X Primary ExaminerVo1odymyr Y. Mayewsky Attorney, Agent, or FirmWenderoth, Lind & Ponack [57] ABSTRACT A pad utilizable in padding, levelling or aligning girders, rails or any other constructional or structural elements. The pad comprises at least one thermoplastic plate member and an electric heater for heating the thermoplastic plate member to soften or melt to cause the overall thickness of the padding material to be reduced to a value sufficient to bring an article or machine to a predetermined level. The plate member is made of a thermoplastic polyester material of a composition which substantially comprises a crystalline polyester segment having a high melting point or a softening point and a non-crystalline polymer segment having a low melting point.

16 Claims, 11 Drawing Figures US. Patent Dec. 2, 1975 Sheet 1 of3 3,924,103

FIG. 2

O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O FIG. 6

FIG. 4

FIG. 5

alllfl ll zllllei Patent Dec. 2, 1975 Sheet 2 of3 3,924,103

FIG. 7

FIG. 8

24' 24 6 25 24 2 J I 5 p I I FIG. 9

I UNDER Slo- VARIETY 1[ 0 8 E8 UNDER V VARIETY I O: LIJ E Z3 8 LI. 0 2 D O 2 Iio ls'o I90 260 210 220 2'30 TEMP. (c.)

FIG. /0

DIS PLACEMENT(mm) FIG/l DISPLACEMENT ELECTRICALLY HEATED ALIGNMENT PAD The present invention relates to a padding material utilizable in padding, levelling or aligning girders, rails or any other constructional or structural elements and, more particularly, to a constructional device comprising a body of thermoplastic material having embedded therein an electric heater, which electric heater is, while the constructional device is placed in between a load exerting member and a load receiving member, energized to electrothermally deform the body of thermoplastic material so as to permit the load exerting member to assume a definite position relative to the load receiving member.

It is well known that, when a railway track structure composed of a line of rails is to be erected, the track structure is laid on the roadbed of a railroad which may include either a pavement of ballast or a pavement of slabs of reinforced or prestressed concrete. In addition, it is well known that depending upon the type of the slabs and the amount of loads they may receive, the slab-paved roadbed may not require the use of crossties or sleepers for the support of the rails in a predetermined track gauge. Prior to placement of the railway track structure on the railroad, the roadbed should be prepared to assume a predetermined level as exactly as possible over the-entire length thereof.

However, the exact levelling of the roadbed is difficult and, therefore, for the purpose of compensation for a difference between the actual level of the railway track structure relative to the roadbed deviation at one local position and that at another local position, several methods have heretofore been practised. One of these methods is the use of filler pads, made of compressed rubber, which are individually placed between the rails and the roadbed, or the crossties if employed, in spaced relation to each other in the lengthwise direction of the track. Another one of these methods is the use of bags placed in a substantially similar manner as the filler pads and subsequently filled with a grout of synthetic material which is solidificable upon evaporation of solvent.

According to the first mentioned method, a considerable number of filler pads are required which are of different thickness, right for various positions in the roadbed where the track tends to sink below its specific level. In other words, the filler pads are required in a number substantially corresponding to the number of deviations in the roadbed level. On the other hand, according to the second mentioned method, because of the grout in a fluid state, maintenance, handling and grouting operation with the grout are all difficult.

In addition to the individual disadvantages referred to above, performance of any of the first and second mentioned methods is complicated in procedure and is time-consuming and labor-consuming.

In the case where an architectural frame or girder or a heavy-duty machine is to be installed on a levelled concrete floor, some anchor bolts are utilized. These anchor bolts are embedded in portion of the concrete floor where the architectural frame or the heavy-duty machine is to be installed. If at least that portion of the concrete floor fails to be levelled, the usual procedure to bring the architectural frame or the machine to a predetermined level has heretofore been carried out by reforming that portion of the concrete floor so as to achieve a predetermined level while the individual anchor bolts are accurately positioned so as to align with the architectural frame or the machine. In this procedure, some disadvantages are still found in that complete solidificationof concrete material used to reform the portion of the floor creates delays and in that alignment of theindividual anchor bolts during levelling of that portion of the floor is difficult. In other words, this levelling procedure is complicated and, similarly, timeconsuming and labor-consuming.

In order to avoid the disadvantages and inconveniences referred to above, there has recently been pro posed a padding material which includes an electric heater of a substantially plate-like or planar shape fitted to one surface of a thermoplastic plate member or preferably sandwiched between a pair of thermoplastic plate members. The padding material of the construction referred to above is utilized in practice in the following manner.

Firstly, the padding material is placed in position between a foundation, for example, each of tie plates on the roadbed, and the bottom or root of a rail forming a part of the railway track structure. The electric heater is subsequently energized to heat the thermoplastic plate members. The thermoplastic material which constitutes the individual plate members being heated becomes softened and, therefore, deforms as it receives an external pushing force, that is, the weight of the rail acting on the plate members in a direction perpendicular to the plane of the plate members, that is, in a direction of the thickness of the plate members. In this way, bringing the rail to a desired or predetermined level can be carried out by the thickness deformation of the plate members.

The padding material of the type heretofore proposed can also be utilized not only in levelling, but in padding or aligning any other constructional or structural elements in a substantiallysimilar way as the padding material of the present invention would be practised.

Insofar as railway construction is concerned, the padding material heretofore proposed is successful in substantially eliminating the disadvantages and inconveniences inherent in the conventional levelling technique. The use of the padding material in fact facilitates levelling, but in order for the padding material to exhibit highly reliable performance, it has been recognized that material for the plate member or plate members should satisfy the following requirements.

I. Be a thermoplastic,

2. Be capable of exhibiting a sufficient melt viscosity even when heated to a temperature above the softening point thereof,

3. Have a relatively high load bearing properties in terms of compression creep, compressive stress and impact strength,

4. Have a sufficient elasticity, in terms of spring constant, compressive modulus and hardness, to an extent that vibrations can be absorbed, and

5. Exhibit no substantial change in physical property even when subjected to a temperature within a practical range of from the brittle point temperature of below --40C. to the minimum fluidizing temperature of above +C., which minimum fluidizing temperature means the temperature at which the material commences to fluidize.

However, the material satisfying each item of the above requirements is not known. A synthetic thermoplastic resinnowcommercially available is apt to ex- 3 hibit such a characteristic that the melt viscosity reduces rapidly when it is heated to a temperature above the softening point. If this commercially available thermoplastic resin is used as the material for the plate members of the padding'material, a sufficient levelling or padding cannot be appreciated because the resin tends to readily fluidize before the levelling or padding is complete.

A certain synthetic resin having a sufficient hardness is also commercially available. However, this synthetic resin does not exhibit a sufficient elasticity and has no property of absorbing vibrations and/or impact applied thereto and, therefore, if it is used as material for the plate members of the padding material, the latter will readily be fractured under the influence of vibration and/or impact and cannot accordingly be used where vibrations and/or impact is present.

As a synthetic thermoplastic resin having a sufficient elasticity, ethylenevinyl acetate copolymer, styrenebutadiene block copolymer and polyurethane elastomer are'known. However, the above two copolymers have common drawbacks in that, when subjected to a predetermined load, any of these copolymers is greatly deformed and in that considerable change in physical property occurs when any of these copolymers is handled under conditions in which the temperature varies from 40C. to +80C. On the other hand, the elastomer lacks a stability in terms of water, weather and heat resistance.

Accordingly, an essential object of the present invention is to provide an improved padding material which is effective to facilitate levelling, padding or aligning work accurately and reliably, thereby substantially eliminating the disadvantages and inconveniences heretofore encountered in similar work.

Another important object of the present invention is to provide an improved padding material of the type referred to above, which exhibits a sufficient durability under severe conditions in which it is used.

A further object of the present invention is to provide an improved padding material of the type referred to above, in which a synthetic resin satisfying the foregoing requirements is utilized to improve the overall performance and durability thereof.

According to the present invention, there is provided an improved padding material which comprises at least one plate member, made of thennoplastic material, and at least one electric heater fitted to one surface of the plate member. The padding material of the above construction may include a covering enclosing the plate member and the heater together, said covering being made of a sheet of thermal insulating material, for example, non-woven sheet of polyester.

The respective numbers of the plate member and the heater may not be limited to one. Two heaters for one plate member can be employed, in which case the individual heaters are fitted to both surfaces of the plate member. Moreover, one heater for two plate members may be employed, in which case the heater is sandwiched or held in position between the individual plate members. In the case where three or more plate members are employed, the heater is preferably employed in a corresponding number. By way of example, assuming that the number of the plate members employed is three, at least two heaters can be employed which are respectively held in position between one plate memher and the next adjacent plate member, or four heaters can be employed at maximum, two of which are re- 4 spectively held in position between one plate member and the next adjacent plate member while the other two are respectively fitted to the outer surfaces of the assembled plate members.

In the case where two or more electric heaters are employed, they may electrically be series-connected, or otherwise connected to a common source of electric power through a suitable connection, for example, by the use of a power distributing coupler.

The electric heater is preferably of a planar type similar to that employed in an electric blanket. Although any other type of electric heater may be employed, the use of the planar heater is preferred for the reason which will become apparent from the later description.

Material for the plate member may be a thermoplastic block-copolymerized polyester of a particular composition herein disclosed, which has a melt'viscosity of less temperature dependence; a minimum fluidizing temperature of above C., preferably, within the range of to 220C. and, more preferably, above the range of to 220C.; a brittle point temperature of not higher than 40C., preferably, not higher than 50C. and, more preferably, not higher than 60C.; a compressive stress within the range of 5 to 350 kglcm preferably, 10 to 200 kg/cm and, more preferably, 30 to 150 kglcm at the time 5% deformation thereof takes place; a compressive modulus of 300 to 7,000 kglcm preferably, 300 to 5,000 kg/cm and, more preferably, 400 to 4,000 kglcm an impact strength of not less than 10 kg.cm/cm, preferably, above 30 kg.cm/cm and, more preferably, above 50 kg.cm/cm; and a hardness of not less than 20, preferably, above 25, as measured by the use of a D-type Shore durometer.

More specifically, the material for the plate member comprises a block copolymer of a crystalline polyester segment with an amorphous polymer segment. The crystalline polyester segment is of a kind having a high melting point, for example, not less than l50C., when a high molecular weight polymer is produced from the component thereof alone in the form of polyester selected from the group consisting of polylactone, aromatic polyesterether and polyester, said polyester containing an acidic component in the form of aromatic dicarboxylic acid residue and a glycol component which contain one or more compounds selected from the group of an aliphatic diol residue having 3 to 10 carbon atoms, an aromatic diol residue and alicyclic diol residue. This crystalline polyester segment is employed in an amount within the range of 99 to 15 wt% relative to the total weight of the block copolymer. The non-crystalline polymer segment is of a kind having a melting point lower than that of the crystalline polyester segment and is employed in an amount within the range of l to 85 wt% relative to the total weight of the block copolymer.

One or more parameters such as amount and composition of the crystalline polyester segment to be used and amount and composition of the non-crystalline polymer segment to be used, should be determined in consideration of the purpose for which the resultant padding material is utilized and also of desired characteristics the resultant padding material may have. By way of example, if the resultant padding material is desired to have relatively high load bearing properties and a relatively high vibration-damping property, the block copolymer as material for the plate member preferably contains the non-crystalline polymer segment in a relatively great amount within the specific range. If the resultant padding material is desired to have relatively high load bearing properties and relatively high hardness and mechanical strength, the block copolymer preferably contains the non-crystalline polymer segment in a relatively small amount while the crystalline polyester segmentis of either the terephthalic acid type or naphthalene dicarboxylic acid type. Moreover, if the resultant padding material is desired to be capable of withstanding a highly elevated temperature, the block copolymerwhich contains, as the crystallinepolyester segment, a polyester prepared from an aromatic dicarboxylic acid, such as terephthalic acid, naphthalene dicarboxylic acid or l,2-bis( 4,4-dicarboxyphenoxy) ethane, and an aliphatic diol having 3 to carbon atoms, is preferably employed. If the resultant padding material is desired to have a relatively high oil resistance, the block copolymer which contains one of polylactones as the crystalline polyester segment or which contains an aliphatic polyester as the amorphous polymer segment, is preferably employed. Furthermore, if the resultant padding material is desired to have a relatively excellent'cold-temperatureresistance, the block copolymer which contains a polytetramethylene glycol as the noncrystalline polymer segment is preferably employed.

In view of the nature and construction of the padding material according to the present invention, not only levelling operation can be facilitated, but an accurate and effective levelling can be realized. The padding material according to the present invention has many fields of application. By way of example, in view of the fact that the padding material is imparted a sufficient elasticity to provide a relatively high vibration damping property with improvement in load bearing properties, the padding material herein disclosed can be utilized to bring a precision machine to a predetermined level irrespective of the surface condition of a foundation or floor on which the machine is to be installed.

The padding material herein disclosed is also suited for use in levelling practised not only during machine installation, but during railway construction or building construction, and under any circumstance even where the padding'material might be exposed to a rapid variation in ambient temperature for a substantially long period of time.

In additiomthe levelling pad herein disclosed can also be used as a padding device or an aligning device.

' An example of the use as a padding device would be filling a gap or clearance between a certain structural member, for example, stationarily held in position, and a subsequently adjacently installed structural member, the final size of which gap or clearance could have been neither predicated nor measured at the time of installation of the adjacent structural member relative to the certain structural member. In this case, the padding device in the form of the padding material herein disclosed may be executed in such a manner as to place it in the gap or clearance prior to final fixing of the size of such gap or clearance, subsequently to energize the built-in heater to heat the plate member forming a part of the padding material, and finally to move the subsesired'orpredetermined size can be achieved in the gap I or clearanceSupply of electric power to the built-in heater may be interrupted, at the time or shortly before the gap or clearance achieves the final size, to allow the 6 softened plate member to solidify with its thickness deformed to a value corresponding to the final size of the gap or clearance.

In the case where the structural members referred to above are, so far from the gap or clearance between these members being filled, desired to be placed or installed on the same level and in line with each other, it will be readily understood that the padding material herein disclosed can, if placed between one or both of the structural members and the floor or foundation and operated in a similar manner as hereinbefore described, act as the aligning device.

In any event, if one or more of reinforcing agent, modifier, ultraviolet ray absorbent, fire proofing agent and any other additives are added to the block copolymer during the preparation thereof, additional and/or cumulative properties attributable from the addition of one or more of these additives can be imparted to the resultant padding material in addition to those attributable from the selection of material for the crystalline polyester segment and non-crystalline polymer segment.

The crystalline polyester segment selected from the group consisting of polyester, polylactone and aromatic polyesterether forming a component of the block copolymer which is used as the material for the plate member generally represents a crystalline structure, when formed into the block copolymer with the noncrystalline polymer segment, has a melting point of not less than C. when formed into a high polymer, and contains an acidic component, which is an aromatic dicarboxylic acid residue, and a glycol component selected from the group consisting of an aliphatic diol residue having 3 to 10 carbon atoms, an aromatic diol residue and an alicyclic diol residue.

Typical examples of this crystalline polyester segment are a homopolyester containing a diol residue selected from the group consisting of an aromatic dicarboxylic acid residue, such as terephthalic acid, isophthalic acid, 1,5-naphthalene dicarboxylic acid, 2,6- naphthalene dicarboxylic acid, 2,7-naphthalene dicarboxylic acid, 4,4-biphenyl dicarboxylic acid, bis(4-carboxyphenyl) methane or 4,4-sulfonyldibenzoic acid, an aliphatic diol residue having 3 to 10 carbon atoms, such as propylene glycol, tetramethylene glycol, pentamethylene glycol, 2,2-dimethyl trimethylene glycol, hexamethylene glycol, decamethylene glycol, pylylene glycol or 1,4-cyclohexane dimethanol, an aromatic diol residue and an alicyclic diol residue; a copolyester containing two or more of the dicarboxylic acid residue or of the diol residues; a polylactone such as polypivalolactone; a homopolyether ester or copolyether ester containing a hydroxy acid residue, such as 4-(2-hydroxyethoxy) benzoic acid or 4-hydroxybenzoic acid; an aromatic polyether ester comprising an aromatic ether dicarboxylic acid residue, such as l,2-bis(4,4-dicarboxyphenoxy) ethane or l,2-bis(4,4'-dicarboxymethyl phenoxy) ethane, and said diol residue; and any one of copolyesters containing a combination of said dicarboxylic acid, hydroxylic acid and diol residues, which has the foregoing properties.

Preferably, the crystalline polyester segment is a polyester comprising the aromatic dicarboxylic acid residue and the diol residue selected from the group consisting of the aliphatic diol residue having 3 to 10 carbon atoms, the aromatic diol residue and the alicyclic diol residue and, more preferably, a copolyester or polyester containing the terephthalic acid residue and the aliphatic glycol residue having 3 to 10 carbon atoms, which polyester contains tetramethylene terephthalate units in 'an amount of 60 mol% or more.

The amount of the crystalline polyester segment contained in the resultant block copolymer is within the range of 99 to 15 wt%, preferably within the range of 95 to 40 wt%, more preferably within the range of 90 to 60 wt%, relative to the total weight of the resultant block copolymer.

The non-crystalline polymer segment forming the other component of the block copolymer represents a substantially non-crystalline structure, when formed into the block copolymer with the crystalline polyester segment, and has a melting point or a softening point not more than 80C. and a molecular weight within the range of 400 to 8,000, preferably within the range of 600 to 6,000.

A polyether glycol such as represented by the following formula is an example of this non-crystalline polymer segment, which may be utilized in the present invention.

HO(RO),,H wherein R represents either an alkylene group or a polymethylene group and n is a number selected such as to give the polyether glycol a molecular weight within the range of 400 to 8,000.

More particularly, the non-crystalline polymer segment may be a polyether glycol such as polyethylene glycol, polypropylene glycol or polytetramethylene glycol, a mixture of the polyether glycol components or a copolymerized polyether glycol prepared from the polyether glycol components.

A condensed aliphatic polyester comprising an aliphatic dicarboxylic acid residue such as one having 2 to 12 carbon atoms and an aliphatic glycol residue such as one having 2 to 10 carbon atoms, an aliphatic polyester, for example, polyethylene adipate, polytetramethylene adipate, polyethylene sebacate, polyneopentyl sebacate, polytetramethylene azelate, polytetramethylene dodecanate and polyhexamethylene azelate, which comprises a polylactone such as poly-e-caprolactone or polyvalerolactone; an aliphatic copolyester prepared from two or more of the aliphatic dicarboxylic acids or glycols; or a polyester-polyether block copolymer comprising the aliphatic polyester and a polyether can, so far as having the foregoing properties, be employed as the non-crystalline polymer segment.

Of these components forming the non-crystalline polymer segment, any of those represented by the aforesaid formula, that is, HO( RO),,H, is preferred and the polytetramethylene glycol is more preferred.

The amount of the non-crystalline polymer segment contained in the resultant block copolymer thereof with the crystalline polyester segment is within the range of 1 to 85 wt%, preferably within the range of to 60 wt% and more preferably within the range of to 40 wt%, relative to the total weight of the resultant block copolymer.

Examples of the resultant block copolymer useable in the present invention are a polytetramethylene terephthalate-polyethylene glycol block copolymer; a polytetramethylene terephthalate-polytetramethylene glycol block copolymer; a polytetramethylene terephthalatepolytetramethylene adipate block copolymer; a polytetramethylene terephthalate-polyethylene sebacate block copolymer; a polytetramethylene terephthalatepolyethylene dodecanate block copolymer; a polytetramethylene terephthalate-poly-e-caprolactone block copolymer; a polypivalolactone-poly-e-caprolactone block copolymer; a polytetramethylene terephthalate/isophthalate-polytetramethylene glycol block copolymer; a polytetramethylene terephthalate/naphthalate-polypropylene glycol block copolymer; a polytetramethylene terephthalate/isophthalate-polyethylene dodecanate block copolymer; a polytetramethylene-2,7-naphthalate-polytetramethylene glycol block copolymer; a poly-4-( 2-hydroxyethoxy) benzoatepolytetramethylene glycol block copolymer; and others.

The block copolymer wherein the crystalline polyester segment is employed in the form of the copolyester or polyester containing the aromatic dicarboxylic acid residue and the aliphatic diol residue having 3 to 10 carbon atoms and the non-crystalline polymer segment is employed in the form of polyalkylene glycol or aliphatic polyester, is preferred as the material for the plate member. The block copolymer wherein the crystalline polyester segment is employed in the form of the copolyester or polyester containing the terephthalic acid residue and-the aliphatic diol residue having 3 to 10 carbon atoms and the non-crystalline polymer segment is employed in the form of the polyether glycol having a molecular weight of 600 to 6,000, is more preferred as the material for the plate member. However, the most practical block copolymer as the material for the plate member in view of achievement of the various objects of the present invention may be the one which comprises the polyester in an amount within the range of to 60 wt% relative to the total weight of the block copolymer, said polyester containing the tetramethylene terephthalate. units in an amount of 60 mol% or more of the recurring units, and the polytetramethylene glycol in an amount within the range of 10 to 40 wt% relative to the total weight of the block copolymer, said polytetramethylene glycol having a molecular weight of 600 to 6,000.

The block copolymer utilizable in the present invention can be prepared by the use of any of known polycondensation methods. By way of example, one of the methods which may be employed to prepare the block copolymer utilizable in the present invention as the material for the plate member is such that the aromatic dicarboxylic acid or its dimethyl ester, a diol component forming the non-crystalline polymer segment and a diol having a relatively small molecular weight are heated to about to 260C. in the presence of a catalyst, water or methanol which has been formed during the polycondensation reaction or ester exchange reaction is subsequently removed, and an excessive amount of the diol having the small molecular weight is finally removed from the resultant prepolymer in a substantially vacuum atmosphere to give the block copolymer of a high polymerization degree.

Another method which may similarly be employed is such that a previously prepared prepolymer forming the crystalline polyester segment and a previously prepared prepolymer forming the non-crystalline polymer segment are mixed and reacted with a difunctional chain-extending agent of a type capable of reacting with the terminal group of any of these prepolymers and, thereafter, the resultant volatile component is removed while the system is held in a substantially high vacuum atmosphere, thereby giving the block copoly mer. A further method which may similarly be employed is such that a crystalline polyester of a high polymerization degree having a relatively high melting point and lactones are mixed while heated and subse-.

quently subjected to the ester exchange reaction while concurrently subjected to ring opening-polymerization, so as to give the block copolymer.

In most cases, the block copolymer has a number of favorable properties suitable for the material for the plate member. However, one or all of a thermal-oxidation preventing agent, an ultraviolet ray absorbent and a hydrolysis preventing agent may be added to the block copolymer during the preparation thereof to stabilize the block copolymer against thermal oxidation, ultraviolet rays and/or hydrolysis, respectively. Examples of the thermal oxidation preventing agent which may be employed are phenols and their derivatives, aromatic amines, thiopropionic acid esters, and so on. Examples of the ultraviolet ray absorbent which may be employed are substituted benzophenones, substituted benzotriazoles and so on while examples of the hydrolysis preventing agent which may be employed are polycarbodiimides and others.

Any suitable powdered or fibrous filler material such as carbon black, silica, calcium carbonate, glass fiber, carbon fiber or asbestos may be added to the block copolymer. Addition of the filler material is advantageous in that the elastic modulus of material can be improved and the melt viscosity of a component forming the block copolymer,-at the time said component is heated to an elevated temperature substantially above the softening point thereof, can also be improved. This means that the resultant levelling pad can advantageously used to facilitate the levelling or padding work in an accurate manner.

Furthermore, the block copolymer may contain one or both of pigment and proofing agent if desired.

As the material for the plate member, the block copolymer of the composition, as hereinbefore fully described, can, because of its being thermoplastic, be molded into a desired shape of the plate member by any known method, for example, by means of an injection molding technique, an extrusion molding technique or a compression molding technique. The shape and size of the plate member may be selected in consideration of the gap or clearance where the padding material is to be installed.

These and other objects and features of the present invention will readily become understood from the following description taken in conjunction with a preferred embodiment thereof with reference to the accompanying drawings, in which:

FIG. 1 is a schematic perspective view of 'a padding material according to the present invention, with a portion thereof broken away to show the construction thereof,

FIG. 2 is a top plan view of a thermoplastic plate member employed in the padding material of FIG. 1,

FIG. 3 is a top plan view of an electric heater employed in the padding material of FIG. 1,

FIG. 4 is a cross sectional view taken along the line IV--IV in FIG. 1,

FIG. 5 is a cross sectional view taken along the line VV in FIG. 1,

FIG. 6 is a cross sectional view, on an enlarged scale, of a portion of FIG. 5,

FIG. 7 is a schematic sectional view of a portion of a railway track structure as viewed in a direction parallel to the lengthwise direction of a rail,

FIG. 8 is a schematic side sectional view of the railway track structure as viewed in a direction perpendicular to the lengthwise direction of the rail,

FIG. 9 is a graph illustrating variation of the viscosity of the thermoplastic plate member in relation to variation of the temperature,

FIG. 10 is a graph illustrating the amount of displacement of the thickness of the padding material before operated, in relation to variation of the load applied thereto, and

FIG. 11 is a graph illustrating the amount of displacement of the thickness of the padding material after having been operated, in relation to variation of the load applied thereto.

Before the description of the present invention proceeds, it should be noted that, for the purpose of facilitation of understanding of the present invention, the padding material according to the present invention will now be described as having a substantially rectangular configuration and as used in bringing a rail to a predetermined or required level.

Referring first to FIGS. 1 to 6, a padding material comprises a pair of plate members 1 of the same size and made of the block copolymer of the composition as hereinbefore fully described, and a planar electric heater 5 sandwiched or held in position between these plate members 1. Depending upon the width at the bottom or root of the rail to be levelled and the length of a tie plate to be placed on a crosstie or a slab under the rail, as will be described later, each of the plate members 1 for the padding material used for this purpose may, for example, be 5 mm. in thickness, mm. in width and mm. in length.

Each of the plate members 1 is formed with a plurality of holes 2 each being, for example, circular in crosssection and extending completely through the thickness of the plate member 1. If reduction of the sum of the thicknesses of the plate members 1 in an amount of approximately 4 mm. is desired (which is achieved by heating the plate members 1 so as to deform under loaded condition in such a manner as will be described later), the sum of the total cross-sectional areas or volumes of the holes 2 in both of the plate members 1 preferably occupies about 40% of the sum of the total surface areas or volumes of both of the plate members 1. Accordingly, so far as the above described dimensions of each of the plate members 1 are concerned, each of the holes 2 may, for example, have a diameter of 10 The holes 2 in both of the plate members 1 act as means for accommodating portion of the thermoplastic resin forming the individual plate members 1 to permit the latter to be reduced in thickness by the load imposed upon the padding material, at the time said plate members 1 are heated to soften or melt. In other words, when the heater 5 is energized to heat the plate members I while the load is imposed on the padding material so as to act in a substantial direction of thickness of the padding material, the individual plate members 1 begins to fluidize permitting the thickness of each of the plate members 1 to be reduced while the fluidized portion of the individual plate members 1 substantially fills up the holes 2. Therefore, so long as that portion of the plate members in a fluidized state can be accommodated in compensation for reduction of the sum of the total thicknesses of the individual plate members 1, not only may each of the holes 2 have a cross-sectional shape other than the circular shape, but also a plurality of grooves or a plurality of projections may be employed in place of the illustrated holes 2, in which case the grooves or projection should be formed on one of the surfaces of each of the place members 1 which faces the planar heater 5. Moreover, if the circumstance permits, the block copolymer for the individual plate members 1 may be in the form of a sintered thermoplastic resin prepared by sintering a thermoplastic resin powder to provide porosity in each of the plate members 1.

The holes 2 or any other substitutes therefor are not always necessary depending upon the use of the padding material of the present invention. However, the provision of the holes 2 or their substitutes is recommended in view of the fact that reduction in thickness of the padding material can readily be achieved and, in addition a handsome finish can be achieved.

As best shown in FIGS. and 6, each of the plate members 1 has both sides 3 inclined at an acute angle relative to the plane of the planar heater 5 so that, when both of the plate members 1 are secured, in such a manner as will be described later, with the heater 5 held in position between these plate members 1, substantially inwardly extending V -shaped grooves are respectively formed as at 4 on both sides of the resultant padding material. These grooves 4 function in a substantially similar manner as the holes 2.

The planar heater 5 is, as best shown in FIG. 3, is in the from of a substantially flat, woven heating mat 6 of a size having a length substantially equal to the length of each of the plate members and a width greater than the width of each of the plate members by a few millimeters, which woven heating mat 6, has filaments of glass fiber forming the warp and a continuous, thin heating wire 7 forming the woof. Said filaments of glass I fiber and said heating wire 7 are woven together as if to provide a woven cloth. It will therefore be seen that the heating wire 7 extends in a substantially zig-zag manner in the direction of the warp, transversing the filaments of glass fiber.

The heating wire 7 for this purpose may be employed in the form of a copper wire of 0.18 mm. in diameter and the number of substantially equally spaced runs of the continuous heating wire 7 extending in the zigzag manner, is preferably within the range of to per inch.

The planar heater 5 is held in position between the plate members 1 in such a manner as will now be described. As hereinbefore described, the width of the heater 5, more particularly, the width of the woven heating mat 6, is greater than the width of any of the plate members 1. Therefore, both side portions of the woven heating mat 6, after having been secured with respective lengths of electrically insulating, adhesive tape (not shown), are turned up to provide corresponding loops 8, which loops 8 are, when the woven heating mat 6 is held in position between the plate members 1, accommodated within the respective V-shaped grooves 4 each defined by the side faces 3 of the associated plate members 1.

In order to secure the plate members 1 and the planar heater 5 in the aforesaid arrangement, a bonding agent may be used. However, according to the present invention, taking advantage of the thermoplastic resin forming any of the plate members 1, fusion-bonding is employed. This can be achieved in such a manner that, while the heater 5 is held in position between the plate members in the predetermined arrangement. the heater 5 is first temporarily energized for a period of time sufficient to cause the individual surfaces of the plate members 1, which contact the woven heating mat 6, to melt and the plate members with the heater 5 therebetween are subsequently allowed to stand until the melted surfaces of the plate members 1 solidify. It will readily be seen that at the time of completion of the fusion bonding, both surfaces of the woven heating mat 6 have been interlocked with the respective surfaces of the plate members 1.

As best shown in FIG. 1, one of the opposite end faces of any one of the plate members 1 is provided with a pair of terminal members 10, which may, for example, be embedded into the end face of the plate member 1 with respective portions externally projected. These terminal members 10 are respectively connected with opposite ends of the heating wire 7, naked portions adjacent the opposite ends of the heating wire 7 being inserted through individual electrically insulating sheathings ll. Extending from the terminal members 10 is a pair of lead wires 12 having one ends connected to said terminal members 10 and the other ends connected to a coupler 13, for example, a plug-in jack, for connection with a source of electric power.

The padding material of the above construction may be enclosed, or otherwise packed, within a covering 9 made of a non-woven polyester sheet of 0.1 to 0.2 mm. in thickness. The use of the covering 9 is advantageous in that a loss of thermal energy originating from the energized heating wire 7 can be substantially reduced.

It is to be noted that although the heating wire 7 has been described as extending in the substantially zig-zag manner, it may be arranged in a substantially spiral or coiled configuration which is recommended in case where the padding material is desired to be circular in shape.

It isalso to be noted that the term planar heater" employed in this specification and appended claims is intended to mean a heater, such as designated by 5 of the above construction, of a type capable of emitting heat energy uniformly from at least one surface thereof in a direction substantially perpendicular to said surface. The employment of this type of heater as practised in the present invention is particularly advantageous in respect that the whole surface of each of the plate members 1 which contacts the heater should be softened or melted uniformly to facilitate simultaneous displacement of local points in each plate member 1 in the direction of thickness of said plate member in accordance with distribution of the load applied thereon.

The padding material of the aforesaid construction is practically used in such a manner as will now be described with particular reference to FIGS. 7 and 8.

Before describing the manner to use the padding material of the present invention, a typical roadbed construction will first be described. The roadbed in the illustrated embodiment is shown in the form of a concrete roadbed 21 and includes slabs 22, for example, 5 meters in length and made of reinforced or prestressed concrete, which slabs are paved end-to-end on the upper surface of the concrete roadbed 22. Secured on the upper surface of the pavement of the slabs 22 and equally spaced, for example, 0.6 meter from each other in a straight line are tie plates 23 of a shape substantially as shown in FIG. 7. A length of rail 26 is to be supported on the tie plates 23.

Assuming that the upper surface of the foundation which is defined by the pavement of the slabs 22 and on which the tie plates'23 rest in the straight line is rough, there will be a possibility of formation of a clearance betweenjthe bottom of someof recesses 23a in the respective tie plates 23 and the bottom face of the rail 26 when the latter is placed on the tie plates 23 with the bottom thereof engaged in the recesses 23a, and in an extreme case, the rail 26 will extend, for example, diverging from the horizontal level.

In order to avoid this possibility, prior to the rail 26 being fixed to the tie plates 23, a required number of padding materials, generally indicated by 24 and each being of the construction as hereinbefore fully described, are placed one for each tie plate and held in position within the recesses 23a of the respective tie plates 23, and the rail 26 is subsequently lowered to rest on the padding materials 24. At this time, rubber pads 25 corresponding in number to the padding materials 24 employed may be placed in between the padding materials 24 and the bottom face of the rail 26, if desired, for substantially absorbing shocks which may be created as a train runs on the track.

If the planar heaters of the respective padding materials 24 are energized, for example, merely by connecting the individual plug-in jacks 13 to the common source of electric power, to heat the plate members 1 in the manner as hereinbefore described, each of the plate members 1 of any of the padding materials 24 begins to melt from the surface adjacent the corresponding heater 5 to the opposite surface and, as melting of the plate members 1 in all the padding materials 24 progresses, the rail 26 is lowered by its own gravity while the thickness of each of the padding materials 24 decreases. During this process, the volume of a space where any one of the padding materials 24 is accommodated and which is substantially defined by wall portions, defining the recess 23a in each tie plate 23, and the bottom face of the rail 26 decreases as the rail 26 is lowered, and the melted resin forming each of the plate members 1 tends to extemallyooze from the above mentioned space. However, by the provision of the holes 2 in each plate member 1, this oozing action can be advantageously avoided. In other words, some or all of the holes 2 in the plate members 1 of each of the levelling pads 24 become filled up with the melted resin in a substantially proportional relation to reduction of the volume of said space.

- At the time of completion of lowering of the rail 26 to, for example, the horizontal level above the foundation, the rail 26 becomes supported temporarily on a plurality of adjustment pieces (not shown) that have previously been installed below the rail 26 one for each interval between one tie plate and the next adjacent tie plate. It should be noted that the adjustment pieces may have different height, but should have the top surfaces lying on the same plate in conformity of the horizonal level to which the rail 26 is brought. Shortly before the completion of the rail lowering or simultaneously therewith, the planar heaters 5 of all the padding materials 24 are deenergized to interrupt the heating operation and, thereafter, the individual materials 24 are allowed to stand until the melted portions of the plate members of each material .24 solidify completely while the rail 26 is still supported on the adjustment pieces.

Removal of the adjustment pieces from between the rail 26 and the foundation is effected after the melted portions of the plate members I of each material 24 completely solidify. Insofar as the adjustment pieces or any other like support means are removed after the melted portions of the plate members 1 of each padding material 24 have completely been solidified, removal thereof does not cause the rail 26, once brought to the predetermined level, to displace from the predetermined level. Thus, it will be readily seen that the rail 26 can be accurately brought to the predetermined level even though the space between the foundation, which is defined by the pavement of the slabs 22, and the predetermined level thereabove varies from point to point because of roughness in the surface of the foundation.

More particularly, it has been experienced that bringing one slab 22 exactly to the same level as the next adjacent slab 22 is technically impossible and, therefore, roughness is always present in the pavement of the slabs 22. If the levelling work is carried out by the use of the padding materials according to the present invention, as clearly shown in FIG. 8, the padding material 24 vary in overall thickness in compensation for variation of the space between the foundation and the predetermined level to which the rail 26 is brought, thereby holding the rail 26 to the predetermined level. Comparison of two of the padding materials, such as indicated by 24' and 24", for example, illustrates this fact. The same notion can apply to the other padding materials. Therefore, no gap or clearance will be created between the bottoom face of the rail 26 and the upper surface of any of the rubber pads 25, if the latter are employed, or of any of the padding materials 24 if said rubber pads 25 are not employed.

It should be noted that the padding material 24 and the rubber pad 25 may be reversed in position. Moreover, each padding material 24 may, instead of being placed in between the rail 26 and the tie plate 23, be placed in between the tie plate 23 and the foundation, i.e., the slab 22.

Although in the foregoing embodiment, the tie plates 23 have been described as rigidly secured to the foundation, they may be rigidly secured to crossties or sleepers which are in turn secured to the slabs 22 or to the concrete roadbed 21, or otherwise supported on the known ballast, spaced several ten centimeters from each other.

The following example illustrates the present invention without limiting the same thereto.

EXAMPLE The block copolymer for the material of the individual plate members was prepared in the following varieties of different composition.

Variety I A block copolymer which comprises 3,300 parts of polytetramethylene glycol having a molecular weight of 1,075 on an average, 8,700 parts of dimethyl tere-- Variety II A polytetramethylene terephthalate-polytetramethylene glycol block copolymer which comprises 1,075 parts of polytetramethylene glycol having a molecular weight of 1,075 on an average, 1,100 parts of dimethyl terephthalate and 800 parts of tetramethylene glycol, all being reacted by the known polycondensation method. The polytetramethylene glycol is contained therein as the noncrystalline polymer segment in an amount of 48 wt% relative to the total weight of the block copolymer.

Variety 111 A polytetramethylene terephthalate-poly-e-caprolactone block copolymer which comprises 1,500 parts of polytetramethylene terephthalate having a solution viscosity of lV=0.85 and 500 parts of e-caprolactone reacted thereto. The poly-e-caprolactone was contained therein as the noncrystalline polymer segment in an amount of wt% relative to the total weight of the block copolymer. The solution viscosity of the polytetramethylene terephthalate was measured at a temperature of C. and by the use of a solvent composed of a mixture of 6 moles of phenol and 4 moles of tetrachloroethane.

Variety IV A block coplymer which comprises 1,075 parts of polytetramethylene glycol having a molecular weight of 1,075 on an average, 1,164 parts of dimethyl terephthalate and 810 parts of tetramethylene glycol. The polytetramethylene glycol was contained as the noncrystalline polymer segment in an amount of 46 wt% relative to the total weight of the block copolymer.

Variety V A block copolymer which comprises 1,100 parts of polytetramethylene glycol having a molecular weight of 1,100 on an average, 1,670 parts of dimethyl terephthalate, 470 parts of dimethyl isophthalate and 1,490 parts of tetramethylene glycol. The polytetramethylene glycol was contained as the non-crystalline polymer segment in an amount of 32 wt% relative to the total weight of the block copolymer.

Variety VI A poly-4-(2-hydroxyethoxy)benzoate-polytetramethylene glycol block copolymer which comprises 1,075 parts of polytetramethylene glycol having a molecular weight of 1,075 on an average, and 2,520 parts of methyl-4-(2-hydroxyethoxy)benzoate. The polytetramethylene glycol was contained as the non-crystalline polymer segment in an amount of 30 wt% relative to the total weight of the block copolymer.

Variety Vll A polypivalolactone-poly-e-caprolactone block copolymer which comprises 1,200 parts of polypivalolactone having a solution viscosity of lV=0.85 and 800 parts of e-caprolactone reacted thereto. The poly-ecaprolactone was contained as the non-crystalline polymer segment in an amount of 40 wt% relative to the total weight of the block copolymer.

Variety VIII A block copolymer which comprises 2,150 parts of polytetramethylene glycol having a molecular weight of 1,075 on an average, 5,800 parts of dimethyl terephthalate and 8,800 parts of tetramethylene glycol, all being racted by the known polycondensation method. The non-crystalline polymer segment was contained in an amount of 25.5 wt% relative to the total weight of the block copolymer.

Variety 1X A block copolymer which comprises 2,150 parts of polytetramethylene glycol having a molecular weight of 1,075 on an average, 2,900 parts of dimethyl-2,7-naphthalene dicarboxylate and 2,700 parts of tetramethylene glycol, all being reacted by the known polycondensation method. The non-crystalline polymer segment was contained in an amount of 30 wt% relative to the total weight of the block copolymer.

Comparision A block copolymer which comprises 2,000 parts of polypropylene glycol having a molecular weight of 2,000 on an average, 380 parts of dimethyl terephthalate and 300 parts of tetramethylene glycol, all being reacted ,by the known polycondensation method. The non-crystalline polymer segment was contained in an amount of 85.5 wt% relative to the total weight of the block copolymer.

For the purpose of characteristic testing, injection molded test pieces were each prepared from a dryblended mixture of parts of the block copolymer under the individual Varieties l to IX and Comparision, 0.3 part of 4,4'-thio-bis(6-tert.-butyl-3-methylphenol), 0.3 part of distearyl dithiopropionate and 0.5 part of carbon black (manufactured by Mitsubishi Chemical Industries Ltd. under a tradename Fanes Black HAF). The test results are tabulated in the subsequent entry.

It should be noted that the test piece I contains the block copolymer under Variety l, the test piece 11 the block copolymer under Variety II, the test piece 111 the block copolymer under Variety III, the test piece IV the block copolymer under Variety IV, and so on, and the test piece designated by Com. contains the block copolymer under Comparision.

Types Of Testpieces Types of Test 1 II III IV V VI VII VIII IX COM.

Minimum Fluidizing 200 210 190 170 ZIS 210 150 Temp. (C.)

Brittle Point below below below below below below below below below Temp. (C.) 70 70 7O 7O 70 7O 70 70 -70 -70 Shore Scale-D 50 46 57 43 46 43 40 58 53 15 Hardness Tensile Strength at 490 290 365 270 420 245 230 390 410 120 Breakage (Kg/cm Tensile Elongation 420 470 380 530 460 420 550 400 390 800 at Breakage (7L -continued Types Of Testpieces Types of Test I II III IV V VI VII VIII IX COM.

Tear Strength I45 I24 I81 I 125 40 I00 I75 I60 19 (Kg/cm) Compressive Stress at 55 48 125 44 48 62 40 I30 I I 5 5% Deformation (Kglcm Impact Strength not not not not not not not not not not (Kg.cm/cm) broken broken broken broken broken broken broken broken broken broken Compressive Elastic Modulus (Kglcm 3,400 3,400 4,200 3,200 3,600 3,000 3,000 4,800 3,300 200 Measurement of the particulars of each of the test-- pieces I to IX and Corn. was carried out in the following manner.

Minimum Fluidizing Temperature:

The temperature at the time the polymer heated at a rate of 30C. per minute had just emerged at a rate of cm lsec. from nozzle, 10 mm. in length and 1 mm. in inner diameter, which nozzle is provided in a Koka flow tester.

Brittle Point Temperature:

According to the Japanese Industrial Standards specified by K-630l.

Shore Hardness:

According to ASTM D-2240, Shore-D Scale.

Tensile Strength:

According to the Japanese Industrial Standards specified by K-630l.

Tensile Elongation:

According to the Japanese Industrial Standards specified by K-630l.

Tear Strength:

According to the Japanese Industrial Standards specified by K-630l.

Compressive Stress:

According to the Japanese Industrial Standards specified by K-69l1.

Impact Strength:

According to the Japanese Industrial Standards as specified by K-69l l.

Compressive Elastic Modulus:

shown in FIG. 9, which illustrates curves each representing a relationship between the temperature of the block copolymer and the rate at which the block copolymer under pressure emerged from the nozzle of the flow tester.

The following test was also conducted to determine a difference in plasticity between the padding material of the illustrated construction, which was not operated and as manufactured, and the padding material of the illustrated construction, which has been operated to allow the thickness to reduce in 40% relative to the original thickness, each of these padding materials having the plate members which were each prepared from the copolymer under Variety I. During the test, each of the padding materials tested was first subjected to a load of 5 tons and then with a load of 10 tons and the test results of the fresh padding material and of the operated padding material are shown in FIGS. 10 and l 1, respectively. It is to be noted that each of the broken lines in FIGS. 10 and 11 illustrates how the thickness of the corresponding padding material recovered after the applied load has been removed.

From FIG. 10, it will be readily seen that the fresh padding material has a spring constant of approximately tons per centimeter while the operated levelling pad has a spring constant of approximately 300 tons per centimeter. It will also be understood that the molded article I has a spring constant similar to that of a rubber.

In any event, from the foregoing table and the above test results, any of the molded articles I to IX according to the present invention clearly satisfy the requirements (I) to (5) hereinabove described.

From the foregoing full description of the present invention, it has now become clear that the padding material according to the present invention is effectively utilized in levelling, padding or aligning girders, rails or any other constructional or structural elements merely by heating at least one thermoplastic plate members to allow the thickness thereof to reduce with the concurrent application of pressure thereto. Moreover, the padding material according to the present invention can be easily manufactured at a relatively low cost. No substantial change in physical properties with time occur in the padding material of the present invention and, therefore, the padding material of the present invention can be left where it has been installed without causing any levelling, padding or alignment error.

Although the present invention has been fully described by way of example, it should be noted that various changes and modifications are apparent to those skilled in the art. By way of example, each of the side faces 3 of any of the plate members 1 may be at right angles to the plane of the corresponding plate members. In any event, these changes and modifications should be construed as included within the true scope of the present invention unless otherwise they depart therefrom.

What we claim is:

1. An electrically heated alignment pad which comprises at least one flat plate member of thermoplastic resin, and at least one thin flat electric heater having one surface laying against substantially the whole flat surface of said plate member for heating said plate member to soften said plate member, the other surface of said heater adapted to be held in electrically insulated relationship to the surface supporting it, and to an article to be aligned, said plate member and heater having a structure the thickness of which is reduced when an external compressive force is applied thereto when said plate member is in the heat softened condition, whereby an object through which the compressive force is applied can be moved by the reduction of thickness of the alignment pad for adjusting the position thereof in the direction of the force being applied to the alignment pad; said plate member having a plurality of apertures therein into which portions of said plate member around said apertures flow laterally upon the softening of said plate member when said compressive force is applied thereto; said thermoplastic resin being a block copolymer which comprises a crystalline polyester segment in an amount of 99 to 15 wt% relative to the total weight of said block copolymer and a non-crystalline polymer segment in an amount of l to 85 wt% relative to the total weight of said block copolymer, said crystalline polyester segment being a polyester having a melting point not less than 150 C., and being selected from the group consisting of a polyester, polylactone and aromatic polyesterether, said polyester having an acidic component in the form of an aromatic dicarboxylic residue and a glycol component in the fonn of at least one compound selected from the group consisting of an aliphatic diol residue having 3 to 10 carbon atoms, an aromatic diol residue and an alicyclic diol residue, said non-crystalline. polymer segment having a melting or softening point not more than 80C. in itself and a molecular weight of not less than 400, said block copolymer having a minimum fluidizing temperature of from 130 to 220C, a brittle point temperature of below 40C., a compressive stress of from 5 to 350 kglcm at 5% deformation thereof, a compressive modulus of from 300 to 7,000 kglcm an impact strength of not less than kg.cm/cm and a D-type Shore hardness of not less than 20.

2. A pad as claimed in claim 1, wherein said amount of said non-crystalline polymer segment is within the range of 5 to 60 wt% relative to said total weight of said block copolymer.

3. A pad as claimed in claim 1, wherein said amount of said non-crystalline polymer segment is within the range of 10 to 40 wt% relative to said total weight of said block copolymer.

4. A pad as claimed in claim 1, wherein said crystalline polyester segment is a polyester containing an aromatic dicarboxylic acid residue and one or more diol residues selected from the group consisting of an aliphatic diol residue having 3 to 10 carbon atoms, an alicyclic diol residue and an aromatic diol residue, and wherein said non-crystalline polymer segment is a polyether glycol represented by the fonnular, HO(R O),,H, wherein R is a selected one of alkylene and polymethylene groups and n is a number selected such as to render the polyether glycol to have a molecular weight within the range of 400 to 8,000.

5. A padding material as claimed in claim 17, wherein said crystalline polyester segment is a polyester containing polytetramethylene terephthalate or a copolyester containing tetramethylene terephthalate units in an amount of not less than 60 mol% and wherein said non-crystalline polymer segment is a polyether glycol represented by the formula, HO(RO),,H, wherein R represents alkylene or polymethylene groups and n is a number selected such as to impart to the noncrystalline polymer segment a molecular weight within the range of 400 to 8,000.

6. A pad as claimed in claim 17, wherein said crystalline polyester segment is a polyester containing polyletramethylene terephthalate or a copolyester containing a tetramethylene terephthalate unit in an amount of not less than 60 mol% and wherein said noncrystalline polymer segment is a polytetramethylene glycol.

7. A pad as claimed in claim 5, wherein the polyether glycol represented by the formular l-lO(RO),,H has a molecular weight within the range of 600 to 6,000.

8. A pad as claimed in claim 6, wherein said polytetramethylene glycol has a molecular weight within the range of 600 to 6,000.

9. A pad as claimed in claim ll, wherein said minimum fluidizing temperature is within the range of to 220C, said brittle point temperature is not more than 50C., said compressive stress is within the range of 10 to 200 kglcm said compressive modulus is within the range of 300 to 5,000, said impact strength is not less than 30 kg.cm/cm and said hardness is not less than 25.

10. A pad as claimed in claim 2, wherein said minimum fluidizing temperature is within the range of 130 to 220C, said brittle point temperature is not more than -50C., said compressive stress is within the range of 10 to 200 kglcm said compressive modulus is within the range of 300 to 5,000, said impact strength is not less than 30 kg.cm/cm and said hardness is not less than 25.

11. A pad as claimed in claim 3, wherein said minimum fluidizing temperature is within the range of 130 to 220C, said brittle point temperature is not more than -50C., said compressive stress is within the range of 10 to 200 kg/cm, said compressive modulus is within the range of 300 to 5,000, said impact strength is not less than 30 kg.cm/cm and said hardness is not less than 25.

12. A pad as claimed in claim 4, wherein said minimum fluidizing temperature is within the range of 130 to 220C, said brittle point temperature is not more than 50C., said compressive stress is within the range of 10 to 200 kglcm said compressive modulus is within the range of 300 to 5,000, said impact strength is not less than 30 kg.cm/crn and said hardness is not less than 25.

13. A pad as claimed in claim 5, wherein said minimum fluidizing temperature is within the range of 130 to 220C, said brittle point temperature is not more than -50C., said compressive stress is within the range of 10 to 200 kg/cm said compressive modulus is within the range of 300 to 5,000, said impact strength is not less than 30 kg.cm/cm and said hardness is not less than 25.

14. A pad as claimed in claim 6, wherein said minimum fluidizing temperature is within the range of 130 to 220C said brittle point temperature is not more 21 than -50C., said compressive stress is within the range of to 200 kg/cm said compressive modulus is within the range of 300 to 5,000, said impact strength is not less than 30 kg.cm/cm and said hardness is not less than 25.

15. A pad as claimed in claim 7, wherein said minimum fluidizing temperature is within the range of 130 to 220C, said brittle point temperature is not more than -50C., said compressive stress is within the range of 10 to 200 kglcm said compressive modulus is within the range of 300 to 5,000, said impact strength less than 25. 

1. AN ELECTRICALLY HEATED ALIGNMENT PAD WHICH COMPRISES AT LEAST ONE FLAT PLATE MEMBER OF THERMOPLASTIC RESIN, AND AT LEAST ONE THIN FLAT ELECTRIC HEATER HAVING ONE SURFACE LAYING AGAINST SUBSTANTIALLY THE WHOLE FLAT SURFACE OF SAID PLATE MEMBER FOR HEATING SAID PLATE MEMBER TO SOFTEN SAID PLATE MEMBER, THE OTHER SURFACE OF SAID HEATER ADAPTED TO BE HELD IN ELECTRICALLY INSULATED RELATIONSHIP TO THE SURFACE SUPPORTING IT, AND TO AN ARTICLE TO BE ALIGNED, SAID PLATE MEMBER AND HEATER HAVING A STRUCTURE THICKNESS OF WHICH REDUCED WHEN AN EXTERNAL COMPRESSIVE FORCE IS APPLIED THERETO WHEN SAID PLATE MEMBER IS IN THE HEAT SOFTENED CONDITION, WHEREBY AN OBJECT THROUGH WHICH THE COMPRESSIVE FORCE IS APPLIED CAN BE MOVED BY THE REDUCTION OF THICKNESS OF THE ALIGNMENT PAD FOR ADJUSTING THE POSITION THEREOF IN THE DIRECTION OF THE FORCE BEING APPLIED TO THE ALIGNMENT PAD; SAID PLATE MEMBER HAVING A PLURALITY OF APERTURES THEREIN INTO WHICH PORTIONS OF SAID PLATE MEMBER AROUND SAID APERTURES FLOW LATERALLY UPON THE SOFTENING OF SAID PLATE MEMBER WHEN SAID COMPRESSIVE FORCE IS APPLIED THERETO; SAID THERMOPLASTIC RESIN BEING A BLOCK COPOLYMER WHICH COMPRISES A CRYSTALLINE POLYESTER SEGMENT IN AN AMOUNT OF 99 TO 15 WT% RELATIVE TO THE TOTAL WEIGHT OF SAID BLOCK COPOLYMER AND A NON-CRYSTALLINE POLYMER SEGMENT IN AN AMOUNT OF 1 TO 85 WT% RELATIVE TO THE TOTAL WEIGHT OF SAID BLOCK COPOLYMER, SAID CRYSTALLINE POLYESTER SEGMENT BEING A POLYESTER HAVING A MELTING POINT NOT LESS THAN 150*C., AND BEING SELECTED FROM THE GROUP CONSISTING OF A POLYESTER, PO;YLACTONE AND AROMATIC POLYESTERETHER, SAID POLYESTER HAVING AN ACIDIC COMPONENT IN THE FORM AN AROMATIC DICARBOXYLIC RESIDUE AND A GLYCOL COMPONENT IN THE FORM OF AT LEAST ONE COMPOUND SELECTED FROM THE GROUP CONSISTING OF AN ALIPHATIC DIOL RESIDUE HAVING 3 TO 10 CARBON ATOMS, AN AROMATIC DIOL RESIDUE AND AN ALICYCLIC DIOL RESIDUE, SAID NON-CRYSTALLINE POLYMER SEGMENT HAVING A MELTING OR SOFTENING POINT NOT MORE THAN 80*C. IN ITSELF AND A MOLECULAR WEIGHT OF NOT LESS THAN 400, SAID BLOCK COPOLYMER HAVING A MINIMUM FLUIDIZING TEMPERATURE OF FROM 130* TO 220*C., A BRITTLE POINT TEMPERATURE OF BELOW -40*C., A COMPRESSIVE STRESS OF FROM 5 TO 350 KG/CM2 AT 5% DEFORMATION THEREOF, A COMPRESSIVE MODULUS OF FROM 300 TO 7,000 KG/CM2, AN IMPACT STRENGTH OF NOT LESS THAN 10 KG. CM/CM AND A D-TYPE SHORE HARDNESS OF NOT LESS THAN
 20. 2. A pad as claimed in claim 1, wherein said amount of said non-crystalline polymer segment is within the range of 5 to 60 wt% relative to said total weight of said block copolymer.
 3. A pad as claimed in claim 1, wherein said amount of said non-crystalline polymer segment is within the range of 10 to 40 wt% relative to said total weight of said block copolymer.
 4. A pad as claimed in claim 1, wherein said crystalline polyester segment is a polyester containing an aromatic dicarboxylic acid residue and one or more diol residues selected from the group consisting of an aliphatic diol residue having 3 to 10 carbon atoms, an alicyclic diol residue and an aromatic diol residue, and wherein said non-crystalline polymer segment is a polyether glycol represented by the formular, HO(RO)nH, wherein R is a selected one of alkylene and polymethylene groups and n is a number selected such as to render the polyether glycol to have a molecular weight within the range of 400 to 8,000.
 5. A padding material as claimed in claim 17, wherein said crystalline polyester segment is a polyester containing polytetramethylene terephthalate or a copolyester containing tetramethylene terephthalate units in an amount of not less than 60 mol% and wherein said non-crystalline polymer segment is a polyether glycol represented by the formula, HO(RO)nH, wherein R represents alkylene or polymethylene groups and n is a number selected such as to impart to the noncrystalline polymer segment a molecular weight within the range of 400 to 8,000.
 6. A pad as claimed in claim 17, wherein said crystalline polyester segment is a polyester containing polyletramethylene terephthalate or a copolyester containing a tetramethylene terephthalate unit in an amount of not less than 60 mol% and wherein said noncrystalline polymer segment is a polytetramethylene glycol.
 7. A pad as claimed in claim 5, wherein the polyether glycol represented by the formular HO(RO)nH has a molecular weight within the range of 600 to 6,000.
 8. A pad as claimed in claim 6, wherein said polytetramethylene glycol has a molecular weight within the range of 600 to 6,000.
 9. A pad as claimed in claim 1, wherein said minimum fluidizing temperature is within the range of 130* to 220*C., said brittle point temperature is not more than -50*C., said compressive stress is within the range of 10 to 200 kg/cm2, said compressive modulus is within the range of 300 to 5,000, said impact strength is not less than 30 kg.cm/cm and said hardness is not less than
 25. 10. A pad as claimed in claim 2, wherein said minimum fluidizing temperature is within the range of 130* to 220*C., said brittle point temperature is not more than -50*C., said compressive stress is within the range of 10 to 200 kg/cm2, said compressive modulus is within the range of 300 to 5,000, said impact strength is not less than 30 kg.cm/cm and said hardness is not less than
 25. 11. A pad as claimed in claim 3, wherein said minimum fluidizing temperature is within the range of 130* to 220*C., said brittle point temperature is not more than -50*C., said compressive stress is within the range of 10 to 200 kg/cm2, said compressive modulus is within the range of 300 to 5,000, said impact strength is not less than 30 kg.cm/cm and said hardness is not less than
 25. 12. A pad as claimed in claim 4, wherein said minimum fluidizing temperature is within the range of 130* to 220*C., said brittle point temperature is not more than -50*C., said compressive stress is within the range of 10 to 200 kg/cm2, said compressive modulus is within the range of 300 to 5,000, said impact strength is not less than 30 kg.cm/cm and said hardness is not less than
 25. 13. A pad as claimed in claim 5, wherein said minimum fluidizing temperature is within the range of 130* to 220*C., said brittle point temperature is not more than -50*C., said compressive stress is within the range of 10 to 200 kg/cm2, said compressive modulus is within the range of 300 to 5,000, said impact strength is not less than 30 kg.cm/cm and said hardness is not less than
 25. 14. A pad as claimed in claim 6, wherein said minimum fluidizing temperature is within the range of 130* to 220*C., said brittle point temperature is not more than -50*C., said compressive stress is within the range of 10 to 200 kg/cm2, said compressive modulus is within the range of 300 to 5,000, said impact strength is not less than 30 kg.cm/cm and said hardness is not less than
 25. 15. A pad as claimed in claim 7, wherein said minimum fluidizing temperature is within the range of 130* to 220*C., said brittle point temperature is not more than -50*C., said compressive stress is within the range of 10 to 200 kg/cm2, said compressive modulus is within the range of 300 to 5,000, said impact strength is not less than 30 kg.cm/cm and said hardness is not less than
 25. 16. A pad as claimed in claim 8, wherein said minimum fluidizing temperature is within the range of 130* to 220*C., said brittle point temperature is not more than -50*C., said compressive stress is within the range of 10 to 200 kg/cm2, said compressive modulus is within the range of 300 to 5,000, said impact strength is not less than 30 kg.cm/cm and said hardness is not less than
 25. 